Basically, latch needles have been known from publication DE 36 00 621 C1, for example. They have a base body with a shank terminating in a hook on one end. A latch slot is provided in the shank in the vicinity of the hook. The latch shank of a pivotably supported latch extends into the latch slot. A latch hole is provided on the end of the latch shank, in which case a pivot pin extends through said latch hole. The latch slot is delimited by two lateral walls. An opening is provided in each lateral wall. Both openings are in alignment with each other. The pivot pin extends through the latch hole and is held on its ends in the openings. The outside edges of the two openings are shaped radially inward, so that the pivot pin is held firmly in place relative to its axial direction.
Considering this solution, the latch hole of the latch is pivotably supported on the non-rotatably held pivot pin. At this point, any potential bearing wear is concentrated in a relatively small area.
Publication DE Patent 14407 discloses a latch needle, wherein the two openings provided in the lateral walls have a conical shape. The pivot pin is provided with rivet heads on its ends, said rivet heads being seated in the conical openings. In doing so, the pivot pin provides a rigid connection between the lateral walls.
DE Patent 917 243 discloses latch needles with a co-rotating pivot pin. To do so, a latch hole having a smaller diameter than that of the wall holes is provided. The pivot pin consists of plastic material and has a larger diameter than the latch hole; however, a smaller diameter than the wall holes. If said pivot pin is drawn with the appropriate force into the latch hole, said pin is seated in said hole in a press-fit manner. The ends of the pivot pin projecting from the latch are rotatably supported in the wall holes.
As opposed to this, publication DE 1 906 892 B is based on a pivot pin of steel. Again, the latch hole has a smaller diameter than the wall holes. The two openings provided in the lateral walls have a conical shape. The pivot pin is non-rotatably seated in the latch hole and is provided on its ends with conical heads that are rotatably seated in the conical openings. The pivot pin seated in the latch hole is upset in axial direction so that it is seated in the latch hole in a press-fit manner. The ends projecting from the latch hole form rivet heads shaped like truncated cones, said rivet heads being rotatably supported in the wall holes. Also in this case, the pivot pin establishes a rigid connection between the lateral walls.
Whereas the aforementioned publications basically assume the presence of pivot pins with two ends configured in essentially the same way, publication EP 2 224 048 A1 provides, in at least one embodiment, a pivot pin that has a larger diameter on both sides of the cheek hole than in the latch hole. The pivot pin receives its shape by one-sided upsetting. Consequently, the configuration of this pivot pin is asymmetrical.
The presented known latch bearings can involve problems in view of manufacturing engineering, useful life, precision or they may exhibit other disadvantages.